Angular velocity sensor

Abstract

An angular rate sensor comprises a determination circuit ( 30 ) for inputting an output signal of a full-wave rectifier circuit ( 22 ) and an output signal after amplified by a charge amplifier ( 25 ), and making a determination of abnormality, and an output clamping circuit ( 32 ) activated by an output signal of the determination circuit ( 30 ), if it makes a determination of abnormality, for clamping an output signal of a sensor output terminal at a level close to a power supply voltage or a grounding voltage.

What is claimed is:  
     
       1. An angular rate sensor for a vibration body comprising: 
       means for detecting a level of vibrations of a vibration body;  
       detecting means for detecting a Coriolis' force produced in proportion to an angular rate;  
       a current amplifier for amplifying an output signal of said means of detecting a level of vibrations;  
       a full-wave rectifier circuit for producing a D.C. voltage by rectifying an output signal of a band-pass filter, wherein an output signal of said current amplifier is input;  
       a charge amplifier for inputting and amplifying a signal detected by said detecting means for detecting a Coriolis' force;  
       a synchronous detection circuit for detecting an output signal of a band-pass filter, wherein an output signal of said charge amplifier is input;  
       a sensor output terminal for outputting an output signal of a low-pass filter, wherein an output signal of said synchronous detection circuit is input;  
       a determination circuit for inputting the output signal of said full-wave rectifier circuit and an output signal of said charge amplifier, and for making a determination of abnormality, said determination circuit having an output transistor connected to an abnormality diagnosis terminal, said output transistor turns off if an abnormality is detected which causes a voltage of said abnormality diagnosis terminal to decrease to a level close to a grounding voltage; and  
       an output clamping circuit activated by an output signal of said determination circuit, if said determination circuit makes a determination of abnormality, for clamping the output signal of said sensor output terminal at a level close to a power supply voltage or a grounding voltage.  
     
     
       2. An angular rate sensor for a vibration body comprising: 
       means for detecting a level of vibrations of a vibration body;  
       detecting means for detecting a Coriolis' force produced in proportion to an angular rate;  
       a current amplifier for amplifying an output signal of said means of detecting a level of vibrations;  
       a full-wave rectifier circuit for producing a D.C. voltage by rectifying an output signal of a band-pass filter, wherein an output signal of said current amplifier is input;  
       a charge amplifier for inputting and amplifying a signal detected by said detecting means for detecting a Coriolis' force;  
       a synchronous detection circuit for detecting an output signal of a band-pass filter, wherein an output signal of said charge amplifier is input;  
       a sensor output terminal for outputting an output signal of a low-pass filter, wherein an output signal of said synchronous detection circuit is input;  
       a determination circuit for inputting the output signal of said full-wave rectifier circuit and an output signal of said charge amplifier, and for making a determination of abnormality; and  
       an output clamping circuit having a transistor connected to a sensor output terminal, said output clamping circuit activated by an output signal of said determination circuit, if said determination circuit makes a determination of abnormality, said transistor is forward-biased and said output clamping circuit clamps the output signal of said sensor output terminal at a level close to a power supply voltage.